ReactiveX#5382 Corrected Single.delay documentation

Corrected Single.delay documentation that says that success or error signals will be delayed by the specified amount, but in fact errors are not delayed, only successes.

src/main/java/io/reactivex/Single.java

@@ -1639,7 +1639,7 @@ public final Single<T> delay(long time, TimeUnit unit) {
      * <dd>you specify the {@link Scheduler} where the non-blocking wait and emission happens</dd>
      * </dl>
      *
-     * @param time the time amount to delay the signals
+     * @param time the time amount to delay the emission of the success signal
      * @param unit the time unit
      * @param scheduler the target scheduler to use fro the non-blocking wait and emission
      * @return the new Single instance